Multifocal Lens Spherical Aberration Control for Ghost Image Reduction

Solution Overview

Problem

Current presbyopic corrections, such as bifocal, trifocal, and multifocal lenses and intraocular lenses, suffer from visible 'ghost' images due to simultaneous presence of focused and defocused light, which detract from vision quality, as they cannot effectively manage the combination of optical powers within the same or adjacent regions.

Innovation Solution

The solution involves zone-specific control of spherical aberration, where positive spherical aberration is introduced in the near optical zone and negative spherical aberration in the distance optical zone, ensuring opposite signs for each, to minimize the visibility of defocused images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple optical powers are present in the same or adjacent regions of the optical device (simultaneous vision lenses), then the depth of field is increased for presbyopic patients, but visible ghost images appear due to the combination of focused and defocused light

Engineering Contradiction:

Improvedepth of fieldVSAvoidghost image visibility

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by assigning different spherical aberration characteristics to different zones of the optical device. The near vision zone has positive spherical aberration while the distance vision zone has negative spherical aberration. This local differentiation allows each zone to optimize its focal properties while the opposite signs reduce the visibility of defocused images from the other zone, thereby reducing ghost images while maintaining multifocality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the spherical aberration parameter (sign and magnitude) across different zones of the optical device. By varying the spherical aberration coefficient from positive in the near zone to negative in the distance zone, the patent optimizes the balance between providing multiple focal points and minimizing the visibility of defocused light, thus reducing ghost image formation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If spherical aberration is introduced to increase depth of field, then the range of distances that can be seen is improved, but the quality of the focused image may deteriorate

Engineering Contradiction:

Improvedepth of fieldVSAvoidimage quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by assigning different spherical aberration characteristics to different zones of the optical device. The near vision zone has positive spherical aberration while the distance vision zone has negative spherical aberration. This local differentiation allows each zone to optimize its focal properties while the opposite signs reduce the visibility of defocused images from the other zone, thereby reducing ghost images while maintaining multifocality.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the spherical aberration parameter (sign and magnitude) across different zones of the optical device. By varying the spherical aberration coefficient from positive in the near zone to negative in the distance zone, the patent optimizes the balance between providing multiple focal points and minimizing the visibility of defocused light, thus reducing ghost image formation.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces the visibility of ghost images, enhancing the overall vision quality by optimizing the depth of field and image clarity in presbyopic corrections.

Implementation Method 1

zone-specific control of spherical aberration, where positive spherical aberration is introduced in the near optical zone and negative spherical aberration in the distance optical zone

Methodology Applied

Scientific EffectSpherical aberration:

Data Source

PatentUS8894203B2Multifocal correction providing improved quality of vision

Publication Date: 2014.11.25 WHIRLIGIG LLC

AI summary

This invention describes strategies and devices for improving the visual experience while expanding the depth of field of presbyopic and pseudophakic patients. The invention describes strategies and devices for providing improved image quality and improved visual quality of patients employing simultaneous vision bifocal, trifocal or multifocal corrections or monovision. The invention describes strategies and devices for reducing the visibility of the defocused part of the retinal image generated by simultaneous vision bifocal and multifocal ophthalmic corrections and monovision. The invention describes strategies and devices that employ control of spherical aberration or other similar asphericities to reduce the visibility of defocused ghost images. The invention describes strategies and devices that ensure that negative defocus is always coupled with negative spherical aberration (or similar asphericity), and that positive defocus is always coupled with positive SA (or similar asphericity) as a means to reduce the visibility of defocused ghostimages.